(Circulation. 2000;102:e9050.)
© 2000 American Heart Association, Inc.
Cardiovascular News |
Cardiovascular News
AMIOVIRT
Treatment with amiodarone (Cordarone) or an implantable cardiac defibrillator resulted in the same percent survival in patients with nonischemic dilated cardiomyopathy and asymptomatic, nonsustained ventricular tachycardia, said S. Adam Strickberger, MD, of the University of Michigan in Ann Arbor. Dr Strickberger presented the results of the Amiodarone Versus Implantable Defibrillator in Patients with Nonischemic Cardiomyopathy and Asymptomatic Nonsustained Ventricular Tachycardia (AMIOVERT) study, which was the first to compare the 2 treatments in this particular patient population, at the American Heart Association’s (AHA) Scientific Sessions 2000 in New Orleans on November 15, 2000.
These patients are particularly prone to "sudden death," said Dr Strickberger in describing the rationale for this study. He and his colleagues had anticipated that the implanted defibrillator would demonstrate a survival advantage, and the results took them by surprise. The 102 patients enrolled the study were randomly assigned to have a defibrillator implanted or to receive amiodarone on the following schedule: 400 mg twice a day for 1 week, then 400 mg once a day for 51 weeks, and then 300 mg once a day. Investigators had planned to enroll 438 patients in the study, but the study was terminated early because it became clear that the end point would not be reached. The primary end point was death at 2 years. Mortality risk did not differ significantly between the 2 groups: there were 8 deaths in the group of patients receiving amiodarone and 13 in the defibrillator group. The study lasted for 4 years without a demonstrated survival benefit to either treatment.
VMAC
Nesiritide, a recombinant form of a hormone in the human body, seems to reduce pulmonary capillary wedge pressure and to relieve dyspnea better than placebo or intravenous nitroglycerine 3 hours after the drug is given, said James Young, MD, head of the section of heart failure and cardiac transplant medicine at the Cleveland Clinic Foundation in Ohio. Dr Young, speaking as chair of the Vasodilation in the Management of Acute Congestive Heart Failure (VMAC) study, said the drug is an important tool in the treatment of heart failure. He presented the results of this study at the AHA’s Scientific Sessions 2000 in New Orleans.
"These data suggest a significant and important role for nesiritide in the management of acute, decompensated heart failure," said Dr Young. "This is a new drug and a new concept in treating patients with heart failure. The trial with drug was positive, and it appears more effective than nitroglycerin and better tolerated, with fewer side effects."
VAMC was a phase III, 55-center trial in the United States that enrolled 498 patients who had been admitted to the hospital for the treatment of acute decompensated congestive heart failure. The patients all had dyspnea. They were randomized to 1 of the following 4 arms of the study: those who received a fixed dose of nesiritide intravenously, those who received an adjustable dose of the drug intravenously, those who received intravenous nitroglycerine, and those who received placebo. In addition, all patients received standard-of-care treatment.
Nesiritide was more effective than placebo or nitroglycerine, said Dr Young. The drug is a synthesized form of a B-type natriuretic peptide that is secreted by the heart’s ventricles in reaction to heart failure. The hormone helps restore the body’s salt and water balance, and it improves heart function. It seems to relax blood vessels, increase the excretion of sodium and fluids, and decrease the levels of neurohormones that can constrict blood vessels, cause fluid retention, and elevate blood pressure.
Dr Young said the findings were particularly important in light of the increasing epidemic of heart failure. As many as 5 million Americans suffer from heart failure. Approximately 1 million of them are hospitalized each year at a cost of $8 billion to $15 billion. Heart failure causes the most hospitalizations in the United States in people over the age of 65 years.
C-PORT PCI
The Atlantic Cardiovascular Patient Outcomes Research Team Trial of Primary Percutaneous Coronary Intervention versus Thrombolysis in Acute Myocardial Infarction (C-PORT PCI) determined that treatment with a primary percutaneous coronary intervention was at least as good as thrombolytic therapy in the treatment of acute myocardial infarction, said Thomas Aversano, MD, of Johns Hopkins Medical Institutions in Baltimore, Maryland.
The study enrolled 453 patients at multiple sites around the United States. Patients were randomized to the thrombolytic therapy arm or to the primary percutaneous coronary intervention arm. Those in the thrombolytic arm received aspirin and 48 hours of heparin after thrombolysis. In the percutaneous arm of the study, cardiac catheterization was performed within 60 minutes of the patient’s evaluation in the emergency room. The mean emergency room-to-first balloon inflation time was 90 minutes. Physicians were allowed to use stents and glycoprotein IIb/IIIa inhibitors. No angioplasty was performed if the flow rate was grade 3 with a resolution of the ischemia.
Of the 226 patients assigned to percutaneous treatment, 210 underwent an angiogram and 169 had the procedure performed successfully. The primary end point of the study was the composite of death, nonfatal myocardial infarction, or stroke at 6 months.
The success rate in the percutaneous arm was 91%; stents were used in 70% of the patients, and glycoprotein IIb/IIIa inhibitors were used in 75%. No patient required surgical intervention in this group.
At 6 months, there were 31% fewer deaths in the percutaneous arm, but that reduction did not reach statistical significance, said Dr Aversano. He said the data suggest that percutaneous treatment might be advantageous is some subgroups, such as women, the elderly, and diabetics. "We conclude that primary percutaneous coronary intervention is at least as good, and in some circumstances, superior to thrombolysis for the treatment of acute myocardial infarction in a community hospital without on-site cardiac surgery." However, before such a hospital begins performing primary percutaneous transluminal coronary angioplasty, it must be committed to developing the necessary program and to monitoring the progress of that program. The hospital should perform a certain volume of the procedures and have the procedure ready 24 hours per day, 7 days a week. When asked which treatment is better, Dr Aversano could not answer definitively. "Sometimes one is and sometimes the other," he said.
INHIBIT
A major problem with stents is when a narrowing occurs at the site where a stent is placed, said Ron Waksman, MD, clinical associate professor of cardiology at Georgetown University in Washington, DC. Prior studies have indicated that radiation at the site of the stenosis in the stent can reduce the risk that the artery will narrow there again. In the Intimal Hyperplasia Inhibition with Beta In-Stent Trial (INHIBIT), researchers attempted to study the effect of ß-radiation on such lesions. Physicians at 29 centers enrolled 332 patients with in-stent restenosis, said Dr Waksman at the AHA’s Scientific Sessions 2000 in New Orleans.
"One objective of the study was to examine whether ß-radiation was effective in treating long lesions," he said. Patients were randomized to conventional treatment, which consisted of a balloon or another stent to open the narrowed artery or to the arm where ablation of the lesion was accomplished by ß-radiation. "The dose in this study was 20 Gy at 1 mm from the balloon." At 9 months, patients underwent angiography and evaluation.
The trial showed that ß-radiation was effective in reducing the restenosis, said Dr Waksman. In the radiation group, 26% of patients had restenosis at the site of the previous lesion; 52% of those in the placebo arm had restenosis. The patients in the radiation group had a 56% reduction in the composite end point, which included death, myocardial infarction, and the need for artery revascularization. Only 14% of the patients in the group that received radiation had 1 of the events in the composite end point, compared with 31% in the group that did not receive radiation.
FLORIDA
The drug fluvastatin had no significant effect on the incidence of ischemia when started early after a myocardial infarction, said Dr Anho H. Liem of the Working Group on Cardiovascular Research in the Netherlands. The aim of the Fluvastatin On Risk Diminishing after Acute Myocardial Infarction (FLORIDA) study was to determine whether giving a statin soon after a heart attack can restore endothelial function and prevent postinfarction ischemia.
Within 2 weeks of experiencing a myocardial infarction, 540 patients were randomized to receive 40 mg of fluvastatin twice a day or a placebo. Residual ischemia measurements were performed at baseline, at 6 weeks, and at 1 year. The primary end point of the trial was the presence of residual ischemia on 48-hour ambulatory ECG monitoring at 1 year or any clinical event, such as death, recurrent heart attack, recurrent ischemia requiring hospitalization or the need for percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting.
At 1 year, 30% of the fluvastatin group had experienced 1 of the primary end point events compared with 36% of the placebo group. The researchers concluded that the study indicated no significant benefit from fluvastatin when given early after acute myocardial infarction. Dr Liem said he did not know whether the result would have been different if the study drug had been given immediately after the patient was admitted.
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